Significance of body temperature in elderly patients with sepsis

Abstract

Background Elderly patients have a blunted host response, which may influence vital signs and clinical outcomes of sepsis. This study was aimed to investigate whether the associations between the vital signs and mortality are different in elderly and non-elderly patients with sepsis. Methods This was a retrospective observational study. A Japanese multicenter sepsis cohort (FORECAST, n = 1148) was used for the discovery analyses. Significant discovery results were tested for replication using two validation cohorts of sepsis (JAAMSR, Japan, n = 624; SPH, Canada, n = 1004). Patients were categorized into elderly and non-elderly groups (age ≥ 75 or < 75 years). We tested for association between vital signs (body temperature [BT], heart rate, mean arterial pressure, systolic blood pressure, and respiratory rate) and 90-day in-hospital mortality (primary outcome). Results In the discovery cohort, non-elderly patients with BT < 36.0 °C had significantly increased 90-day mortality (P = 0.025, adjusted hazard ratio 1.70, 95% CI 1.07–2.71). In the validation cohorts, non-elderly patients with BT < 36.0 °C had significantly increased mortality (JAAMSR, P = 0.0024, adjusted hazard ratio 2.05, 95% CI 1.29–3.26; SPH, P = 0.029, adjusted hazard ratio 1.36, 95% CI 1.03–1.80). These differences were not observed in elderly patients in the three cohorts. Associations between the other four vital signs and mortality were not different in elderly and non-elderly patients. The interaction of age and hypothermia/fever was significant (P < 0.05). Conclusions In septic patients, we found mortality in non-elderly sepsis patients was increased with hypothermia and decreased with fever. However, mortality in elderly patients was not associated with BT. These results illuminate the difference in the inflammatory response of the elderly compared to non-elderly sepsis patients.

Hyperthermia is a predictor of high mortality in patients with sepsis

“…In a recent study, Shimazui et al [1] reported that body temperature (BT) on ICU admission exhibited different predictive values in elderly and non-elderly patients with sepsis, and only hypothermia (BT < 36.0°C) was associated with increased mortality in non-elderly patients while hyperthermia (BT > 38.3°C) was not. A few issues should be noted.…”

Mortality in non-elderly septic patients was increased with hypothermia and decreased with fever while mortality in elderly patients was not associated with body temperature: beware of some confounders!

“…We read with great interest the recent article by Shimazui et al who concluded that in septic patients, mortality in non-elderly patients was increased with hypothermia and decreased with fever, while mortality in elderly patients was not associated with body temperature (BT) [1]. We would like to make some comments.…”

“…We would like to make some comments. As was alluded to by the authors themselves, BT measurement can be potentially confounded by various factors, including variation in the site of temperature measurement and whether or not patients receive antipyretics or targeted temperature management [1]. Nearly half of critically ill patients, especially those with septic shock, have or develop acute kidney injury (AKI) and 20-25% need renal replacement therapy (RRT) within the first week of their stay [2].…”

“…Nearly half of critically ill patients, especially those with septic shock, have or develop acute kidney injury (AKI) and 20-25% need renal replacement therapy (RRT) within the first week of their stay [2]. In the study of Shimazui et al, more than 60% of patients in both groups were in septic shock [1]. So, potentially, a third of patients may have had AKI, with 15% receiving continuous RRT (CRRT).…”

“…A recent study found that frailty was a predictor for the development of AKI, increasing the likelihood by more than three times [5]. Therefore, it is a possibility that there were more patients with artificial hypothermia (below 36°C) as a result of RRT in the elderly group of Shimazui et al, introducing a confounder to the study [1]. Unfortunately, data regarding AKI and RRT have not been reported in the study of Shimazui et al, so we are unable to confirm our hypothesis.…”